The nation’s highest court could overturn a state law that accepts late mail-in ballots in Mississippi. 

A state law in Mississippi was the subject of oral arguments heard at the Supreme Court this week. The law allows mail-in ballots to be counted as long as they are postmarked by and received within five business days of Election Day. 

After two hours of oral argument in Watson v. Republican National Committee, a majority of the justices seemed to agree with the challengers, which could lead to the state law being overturned. 

The challengers, the Republican Party of Mississippi and the Libertarian Party of Mississippi, argue that the law conflicts with existing federal laws that set the Tuesday following the first Monday in November as the “election day.” 

The argument reflects that Congress established Election Day by law in 1845, and the Mississippi law directly contradicts it. In 1872, Congress also directed that congressional elections should also occur on the same day. 

The Mississippi law was passed in 2020 in response to the COVID-19 pandemic. 

The case reached the Supreme Court after a three-judge panel of the U.S. Court of Appeals for the 5th Circuit agreed with the challengers that federal law requires all ballots to be received by Election Day. 

The full court of appeals rejected the state’s petition to rehear the case, triggering the Supreme Court’s agreement to take it up in November. 

The update comes shortly after the Republican National Committee petitioned the Supreme Court to reverse a ruling that requires Pennsylvania to count undated and misdated mail-in ballots in early February of this year. 

As a swing state, Pennsylvania has been ground zero in the fight to rein in mail-in voting and restore integrity to federal elections in the United States. 

“Pennsylvania’s mail-in ballot dating requirement is a simple, commonsense safeguard that protects the integrity of the state’s elections,” said RNC Chair Joe Gruters in a recent statement. 

“Counting ballots that are missing basic requirements like a date violates Pennsylvania law and undermines confidence in elections. We urge the Supreme Court to take this case and reaffirm that states can enforce reasonable election rules like Pennsylvania’s date requirements,” he continued. 

In a separate lawsuit, the court declined to previously get involved in Pennsylvania’s mail-in ballot issues. It is now involved in Mississippi’s state issues on the same subject. 

The court’s ruling is expected by late June or early July. It has the potential to impact more than a dozen states that have similar laws in place.